But when you fast: the meaning is “When you go without food for a period of time in order to worship God in a special way.”

When can be “whenever” or “on those occasions that.”

Good News Translation rearranges the two commands in a manner that is more natural for American readers: “wash your face and comb your hair.” Bible en français courant and Die Bibel im heutigen Deutsch follow Good News Translation in this, whereas most English translators retain the literal anoint your head. Some few attempt to update “anoint” by rendering “put oil on your head” (Jerusalem Bible, New International Version), while New American Bible renders “groom your hair,” and An American Translation has “perfume your hair.” One commentator observes that when the disciples fast, they are to give the impression of persons going to a feast. But it may be, as other commentators suggest, that the disciples are simply commanded to look the same when they are fasting and when they are not fasting.

Many translations that have retained anoint your head have in fact misled their readers, who have identified this anointing with that done to those chosen to be kings in the Old Testament, or even to Christ. (“Christ” means “anointed.”) It is better to do something similar to Good News Translation or New American Bible and use a normal term for grooming or combing hair.

In translation it is not necessary to make a distinction between the use of the plural “you” in the Greek text of verse 16 and the singular “you” in verses 17 and 18.

Quoted with permission from Newman, Barclay M. and Stine, Philip C. A Handbook on the Gospel of Matthew. (UBS Handbook Series). New York: UBS, 1988. For this and other handbooks for translators see here .